Webbing

ABSTRACT

THE PRESENT INVENTION PROVIDES A WEBBING WHOSE WARP THREADS CONSIST OF MULTIFILAMENTS OFSYNTHETIC MATERIALS AND WHOSE WEFT THREADS CONSIST OF MONOFILAMENTS OF SYNTHETIC LINEAR POLYESTER MATERIAL.

United States Patent Office 3,606,914 WEBBING Wolfgang Maiwald,Frankfurt am Main, and Helmut Rollser, Hofheim, Taunus, Germany,assignors to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius& Bruning, Frankfurt am Main, Germany No Drawing. Filed May 2, 1969,Ser. No. 821,454 Claims priority, application Germany, May 8, 1968,

Int. Cl. D03d 15/00 US. Cl. 139-420 8 Claims ABSTRACT OF THE DISCLOSUREThe present invention provides a webbing whose warp threads consist ofmultifilaments of synthetic materials and whose weft threads consist ofmonofilaments of synthetic linear polyester material.

It is the object of the present invention to provide a webbing.

Webbings such, for example, as safety belts for motor cars and webbingsfor lifting heavy loads have hitherto been made from fabrics of multifilsynthetic warp and weft threads. To attain a certain essential lateralstability of these webbings, they are generally made of double orcompound fabrics. However, with the use of these double or compoundfabrics the thickness of the webbings is often increased to anundesirable degree. Single fabrics tend to roll up, they acquire theform of a knitted fabric and thus no longer have the necessary bearingor contact surface. This tendency to roll up is highly prejudicial tothe safety factor, for example in the case of safety belts.

Attempts have, therefore, been made to fabricate webbings which areequal in regard to their strength and safety properties to theconventional webbings made of double or compound fabrics, but which havea lesser thickness and do not tend to roll up. A minor thickness of thewebbings without impairment of their strength properties is desirable,for example, for accommodating the safety belts in small wind-updevices.

It is the object of the present invention to provide a webbing whichfulfills the desiderata for such a webbing, i.e. a lesser thickness thanthat of the conventional webbings made of a double or compound fabricwithout the strength and safety properties thereof being impaired. Thewebbing according to the invention consists of a fabric constructed ofsynthetic warp and weft threads, which is characterized in that the warpthreads are multifilaments of synthetic linear material, selected fromthe group consisting of nylon 3, nylon 6, nylon 66, nylon 12,polyacrylonitrile and polyester material and the weft threads aremonofilaments of synthetic linear polyester material.

It is advantageous when not only the warp threads but also the weftthreads consist of synthetic linear polyester material, preferablypolyethylene terephthalate. As synthetic linear polyester material theremay be used any of the conventional filament-forming polyesters andcopolyesters such, for example, aspoly-1,4-cyclohexanedimethanol-terephthalate and the copolyester ofterephthalic acid/isophthalic acid and ethylene glycol. As syntheticlinear polyamide material for the multifil warp threads there may beused mainly polyamide 6 and polyamide 66, however, there may also beused all other filament-forming polyamides and copolyamides.

The thickness of the warp and weft threads in the webbing according tothe invention should correspond to the strength and safety requirementsnecessary in each 3,606,914 Patented Sept. 21, 1971 case. The thicknessof the monofil weft threads preferably lies within the range of from0.15 mm. to 0.4 mm.

It must also be mentioned that the multifil warp threads run in thelongitudinal direction of the webbing and the monofil weft threads runtransversely of this direction.

The webbing according to the invention possesses especially valuableproperties when the fabric constructed of multifil warp threads andmonofil weft threads has been subjected to a heat-setting process Withina temperature range of from about 200 to 230 C., preferably for a periodof at least two minutes. In a webbing of this type the monofil crossthreads readily rupture when greater strain is applied in thelongitudinal direction so that the warp threads are no longer retainedin the fabric and project from the surface of the fabric. Owing theretoit is possible immediately and easily to detect greater strains appliedon the webbings, for example the strain which has acted on a safety beltfor motor cars in the case of an accident. This is very important since,as is known, webbings elongate in the case of high strains until thepoint of their time-to-failure is attained, whereby the webbings becomepractically useless owing to the loss of their capacity of absorbingenergy. The exterior surface of the webbings made of fabrics constructedof multifil warp and weft threads as used hitherto did not show signswhen the stress had exceeded a point which is critical for the safety.The test as to whether the webbings known hitherto had already beensubjected to high strain consists in observing the behavior of thewebbing when subjected to renewed great strain. When the webbings hadnot previously been subjected to great strain they become unserviceableby the strain applied during the test. This drawback is overcome by thewebbing according to the invention when used in the aforesaid preferredmodification, viz when the webbing consists of a heat-set fabric sincethe exterior surface of this webbing immediately shows signs when thewebbing has been subjected to strains beyond the critical point. Therupture of the heat-set monofil cross threads in the case of greatstrains acting in the longitudinal direction on the webbing according tothe invention, can be explained by the fact that the monofils which havebeen set by the heat-setting process in the original bend given by thestructure of the fabric, are compressed into a flatter bend. Thisforcible alteration of the set form then provokes an easy rupture of themonofil weft threads.

It need hardly be mentioned that the point of rupture may be variedwithin certain limits by altering the set of warp threads, the heatsetting conditions, for instance in the dyeing and finishing processes,as well as by the use of monofil weft threads of different thickness.

We claim:

1. Webbing made of a fabric constructed of synthetic 'warp and weftthreads, comprising a single woven fabric, in which the warp threads aremultifilaments of a synthetic linear material, and said weft threadsconsist of monofilaments also of a synthetic linear material.

2. Webbing as claimed in claim 1, wherein both the warp threads and theweft consist of synthetic linear polyester material.

3. Webbing as claimed in claim 1, wherein the synthetic linear polyestermaterial is polyethylene glycol terephthalate.

4. Webbing according to claim 1 wherein the warp threads are selectedfrom the group consisting of polyamide 6, polyamide 66,polyacrylonitrile, polyethylene glycol terephthalate, poly-l,4-cyclohexanedimethanol terephthalate, a copolyester of terephthalicacid/isophthalic acid and ethylene glycol, or polyacrylonitrile.

5. Webbing according to claim 4 wherein the weft threads are of apolyester material.

6. Webbing as claimed in claim 5, wherein the monofil weft threads havea diameter within the range of from 0.15 mm. to 0.4 mm.

7. Webbing as claimed in claim 1 wherein the fabric constructed ofmultifilament warp threads and monofilament weft threads is subjected toa heat setting process within the range of 200 to 230 C. to render saidweft threads in a condition to be easily ruptured when the warp threadsare overstressed, whereby said weft threads after being ruptured nolonger retain the warp threads which project from the surface of thefabric providing a visual indication of the webbing having beenoverstressed.

8. A method of manufacturing a webbing to provide a visual indication ofoverstress after the Webbing has been overstressed, comprising the stepsof weaving a single fabric webbing with multifilament warp threads andconsisting of monofilament weft threads, and then heat setting saidfabric in a temperature ranging from 200 C. to 230 C. to render saidweft threads in an original bent given by the structure of the fabricand thus in a condition to be compressed into a flatter bent andruptured when the warp threads are overstressed, whereby said weftthreads after being ruptured no longer retain the warp threads whichproject from the surface of the fabric 25 4 References Cited UNITEDSTATES PATENTS 2,788,023 4/1957 Renaud 139420X 2,794,450 6/1957 Gatzke139 411 2,812,782 11/1957 Stevens 139- 120 2,903,021 9/1959 Holden eta1. 139426X 3,205,119 9/1965 Paul 161 91 3,296,062 1/1967 Truslow 161 913,322,163 5/1967 Hughes 139383 3,463,202 8/1969 Wildi et al. 1393833,464,459 9/1969 Ballard 139-383 FOREIGN PATENTS 609,946 10/1948 GreatBritain 28Dacron Digest OTHER REFERENCES Federal specification Belt;seat passenger type, automotive; JJB-B 1 85A, Jan. 19, 1960 (pp. 1-3).

JAMES KEE CHI, Primary Examiner US. Cl. X.R. 2872

